Camera system with auto-focus function and control method thereof

ABSTRACT

In accordance with an aspect of the present invention a camera system comprising a lens module capable of linear movement in a direction of an optical axis; a drive portion generating for driving force to move said the lens module; a position sensor portion outputting a electrical signal to detect a position of the lens module; a image sensor portion outputting a electrical signal to capture image of a subject through the lens module; a control portion controlling the magnitude of driving force as the result that is judged by discriminating correct position to focus position of the lens module compared to real output and standard output of the position sensor corresponding to focus position of the subject to be detected as to output of the image sensor portion, wherein the control portion is composed of one chip.

TECHNICAL FIELD

The present invention is related to camera system with auto-focusfunction and control method thereof, and more particularly to camerasystem to control position of the lens module quickly in detail whichused digital camera or telecommunication handset.

BACKGROUND ART

These days the development of digital camera system-making techniqueresult in miniaturization and lightweight, the camera is more and morecommon for telecommunication handset.

The digital camera is improved to have high performance till 3M pixel,furthermore it is to be improved to commercialize 7M.

As the digital camera is improved to have high performance, variousfunction such as optical zoom, auto focusing and image stabilizingfunction is adopted to the digital camera. Among the various functionauto-focusing function is particularly adapted to the digital camera.

The method is used to convert rotation movement into linear movement bytransforming device such as stepping motor or DC motor. However adriving unit is too large, so it is to solve the problem to meettechnical evolution which the handset is to be miniaturization and slim.

Therefore, to solve this problem the method is adopted to shift the lensmodule such as voice coil motor, the driving principle of VCM isdisclosed in Korean patent application laid-open No. 2006-0122125.

The method for using VCM can miniaturize space to occupy the drivingportion, but there are various problems with realization ofauto-focusing function.

It is adopted to open loop control type method which is to control thecurrent to be applied to VCM according to the result of image signal tobe transmitted from image sensor module, but in this case there is aproblem not to supply clear image to user because the focus is notfitted to subject as a result of success or failure lens module toprompt shift to target position.

It is differ from not only assembly deviation in many articles, but alsodriving force used to shift lens module (same displacement) owing toself-weigh as shooting angle in same article. It always outputs samesignals as same target position not to considerate difference in priorart.

In case the same current to be input lens driving part is controlled assame control signal, above mentioned focus of the subject is not fitbecause of difference on displacement shift in same article

DISCLOSURE Technical Problem

Accordingly, the present invention has been made to reduce or overcomethe above-mentioned problems occurring in the prior art and provides acamera which precisely controls the position of lens module by closedloop type controlling method in camera having auto focus function.

Another aspect of the present invention is to provide a camera whichprecisely controls the position of lens module at that times whendeviation of driving force comes about owing to difference of shootingangle or assembly deviation in assembling process.

Another aspect of the present invention is to provide a camera which isable to shorten of auto focusing time as shortening of time toconvergence at that position to specified position.

Technical Solution

In accordance with an aspect of the present invention a camera systemcomprising a lens module capable of linear movement in a direction of anoptical axis; a drive portion generating for driving force to move saidthe lens module; a position sensor portion outputting a electricalsignal to detect a position of the lens module; a image sensor portionoutputting a electrical signal to capture image of a subject through thelens module; a control portion controlling the magnitude of drivingforce as the result that is judged by discriminating correct position tofocus position of the lens module compared to real output and standardoutput of the position sensor corresponding to focus position of thesubject to be detected as to output of the image sensor portion.

In case focus position of the lens module is not to be concluded correctposition, the control portion repeat the first position control processthat discriminate correct position to focus position of the lens moduleincreasing or decreasing to setting magnitude of driving force tillfocus position of the lens module is to be concluded correct position

The control portion controls driving force to continue present positionin case focus position of the lens module is to be concluded correctposition.

The control portion control the driving force according to settingroutine to a position among a plurality of lens module including initialposition and maximum position of the lens module and discriminate theoutput of the image sensor portion in movement, detect the focusposition of lens module fitted to the focus position of a subject as thediscriminating result.

The control portion control the magnitude of driving force generated indrive portion as discriminating the position of the lens module comparedto real output and standard output of the position sensor correspondingto a position in case the lens module is moved to a position among aplurality of the lens module position.

The control portion repeat the second position control process thatdiscriminate correct position to focus position of the lens moduleincreasing or decreasing to setting magnitude of driving force tillfocus position of the lens module is to be concluded correct position incase focus position of the lens module is not to be concluded correctposition.

The control portion control driving force to continue present positionin case focus position of the lens module is to be concluded correctposition.

The control portion save real output of the position sensor at aposition among a plurality of the lens module position before detectingthe initial position, and set output a plurality of lens module positionas standard output adding initial standard position and variation ofoutput through output saved position sensor portion as to the respectiveposition of the lens module.

Respective standard output corresponding to the plurality of lens moduleposition is saved, and the control portion compare real output andstandard output of the position sensor corresponding to a position incase the lens module is moved to a position among a plurality of thelens module position, and calibrate standard output of respectiveposition sensor corresponding to a plurality of lens module position incase the difference is more than the first setting range.

The control portion increase or decrease respective standard output of aplurality of lens module position as the difference of output in casestandard output of position sensor portion is to be calibrated.

The initial position is the position of the lens module in case drivingforce is not activated, the maximum position is the position from theinitial position to position to move maximum in case driving force isactivated, and the setting routine is arranged in order variationcompared initial position of a plurality of the lens module position.

The control portion don't move the lens module as to the position incase focus position is detected in a position

The control portion conclude as focus portion or correct position, incase the difference standard output and real output of position sensorportion is in the second setting range.

The control portion is setting magnitude to be set to change in orderwhen the first position control process or the second position controlprocess.

The control portion is composed of one chip and control driving force asthe quantity of current.

In accordance with an aspect of the present invention a camera systemcomprising a lens module capable of linear movement in a direction of anoptical axis; a drive portion generating for driving force to move saidthe lens module; a position sensor portion outputting a electricalsignal to detect a position of the lens module; a image sensor portionoutputting a electrical signal to capture image of a subject through thelens module; a control portion controlling the magnitude of drivingforce as the result that is judged by discriminating correct position tofocus position of the lens module compared to real output and standardoutput of the position sensor corresponding to focus position of thesubject to be detected as to output of the image sensor portion, whereinthe control portion is composed of one chip.

The camera system further comprise housing having the space toaccommodate the lens module, the drive portion and the position sensorportion.

The housing comprising the first housing having the space accommodatethe lens module, the drive portion and the position sensor portion andthe second housing having the space accommodate the image sensorportion, wherein the second housing is situated on the lower part of thefirst housing to be arranged in a direction of an optical axis, aopening is on the upper surface and lower surface of the first housingand the upper surface of the second housing to assure shooting root ofthe image sensor portion.

The lower part of first housing integral to the upper part of secondhousing, and opening which is to be on the opening of lower surface ofthe first housing and the upper surface of the second housing are closedby infrared line filter.

The position sensor portion is hall sensor.

The drive portion arrange a coil in one potion among the lens module orthe first housing, a magnet is arranged facing the coil in anotherportion among the lens module or the first housing.

The magnet is arranged to a side face, and the coil is arranged facing aside face of the lens module having a magnet in inner side surface ofthe first housing.

One first guide member is arranged in a side surface of lens modulehaving the magnetic to guide the lens module in a direction of anoptical axis, at least one second guide member is to be coming into theinner surface of the first housing having the coil confronting positionto the first guide member.

A concave is extended in a direction of an optical axis at inner part ofthe first guide member and the second guide member, and a stopper iscoming into moving range between maximum position and initial positionin which are upper part and lower part of the second guide member, aball is arranged to respective concave of the first guide member and thesecond guide member to roll in a direction of an optical axis.

The first penetrating hole and the second penetrating hole isrespectively coming into the first guide member and the second guidemember, and the lens module is inserted to the first penetrating holeand the second penetrating hole engaged the first housing by guide barmovable in a direction of an optical axis.

In accordance with an aspect of the present invention the auto focuscontrol method which a lens module and a image sensor portion outputtingelectrical signal capturing a subject from the lens module comprisingthe first step that detect focus position of a substance as outputthrough image sensor portion; and the second step that detect realoutput of position sensor moving the lens module to detected position atthe first step, and discriminate correct focus position of the lensmodule comparing to real output of the position sensor and standardoutput corresponding to the focus position, and control position of thelens module as the discriminating result.

The auto focus control method further comprising the third step whichrepeat the third step that discriminate correct focus position of thelens module moving the lens module to setting displacement till the lensmodule to be fitted at focus position in case the lens module isconcluded to be located correct position at the second step.

Present position of the lens module is to be continued in case the lensmodule is concluded to be located correct position at the second step.

Advantageous Effects

The camera of the present invention have advantage that preciselycontrol position of the lens module adapting to closed loop control typecomparing real output to standard output of position sensor contrary tothe prior art using the open loop control type.

The camera of the present invention have advantage that preciselycontrol position of the lens module because the camera respectivelycontrol according to the magnitude of driving force generated in thedrive portion as to various case such as state of fabricating andassembly, shooting angle and effect of gravity that is to be generatedby movement of lens module. Accordingly the camera of the presentinvention improve the yield of product and expense of quality control,decrease the loss.

The camera of the present invention has advantages that shorten thedetecting time because the camera control precisely of the lens module.The camera of the present invention have advantage that convergence tocontrol position of the lens module more quickly because control themagnitude of driving force comparing real output and pure standardoutput of the position sensor not performing complicated operationprocess in case of closed loop process

DESCRIPTION OF DRAWINGS

FIG. 1 is a exploded perspective view a camera system compositionaccording to according to the first embodiment of the present invention.

FIG. 2 is a cross-sectional view a camera system in assembled stateaccording to the first embodiment of the present invention.

FIG. 3 is a perspective view a camera system showing the sustain panelcomposition according to according to the first embodiment of thepresent invention.

FIG. 4 is a perspective view a camera system according to according tothe first embodiment of the present invention.

FIG. 5 and FIG. 6 are block diagram illustrating a camera systemactivating composition according to the first embodiment of the presentinvention.

FIG. 7 and FIG. 8 are block flow chart illustrating control method ofauto focus in camera system according to the first method and the secondmethod in the first embodiment of the present invention.

FIG. 9 is a exploded perspective view a camera system compositionaccording to according to the second embodiment of the presentinvention.

BEST MODE

The present invention will become more apparent by describing in detailexemplary embodiments thereof with reference to the attached drawings inwhich.

FIG. 1 is a exploded perspective view a camera system compositionaccording to according to the first embodiment of the present invention.FIG. 2 is a cross-sectional view a camera system in assembled stateaccording to according to the first embodiment of the present invention.FIG. 3 is a perspective view a camera system showing the sustain panelcomposition according to according to the first embodiment of thepresent invention.

Referring to FIG. 1 and FIG. 3 the camera comprising that lens module(10) having at least one lens in a direction of an optical axis (1), thefirst housing (20) accommodating the lens module (10) opened uppersurface and a side surface having rectangular parallelepiped shape, thefirst housing cover (21) prohibiting from digressing of lens module (10)engaging with the upper surface of the first housing (20), support panel(30) having inner space to accommodate the lens module with the firsthousing cover (21) engaging with the opened side surface of the firsthousing (20), drive portion (40) moving the lens module (10) in adirection of an optical axis (1) accommodated in inner space of thefirst housing (20), hall sensor portion (50) detecting variation of thelens module (10) accommodated in inner space of the first housing (20),the second housing (23) extended in bottom surface (22) of the firsthousing (20) having rectangular parallelepiped shape departed of thefirst housing (20) through bottom surface (22) and image sensor module(60) accommodated in inner space of the first housing (20).

The image sensor module (60) comprising image sensor (61), flexibleprinted circuit (62) and circuit board (63). The image sensor (61) to bearranged in image surface equipped on circuit board (63) by boding, theflexible printed circuit connected to main circuit board (not shown) ofcamera or handset extended in the circuit board (63). At this time thefirst opening (24) and the second opening (25) is respectively formed atthe first housing cover (21) and the bottom surface (22) of the firsthousing. The edge part of circuit board (63) have saw-like wire bondingsoldering (66) to fix with drive portion circuit board (40 a).

The second housing (23) is opened to bottom surface and fixed to circuitboard (63) covering image sensor (61). At this time image sensor (61)detect the image provided by infrared filter (65) because the secondopening (25) is closed by infrared filter (65). The image sensor (61) isarranged with infrared filter (65) and the lens module (10) in adirection of an optical axis (1).

The inner space of not-opened side surface of lens module guide (26) isformed covering lens module to inhibit from missing in a direction of anoptical axis, and the lens module (10) is guided along in a direction ofan optical axis (1).

The assembly projection (27) is formed at respective edge portionadjacent to opened side surface to be assembled to support panel (30).At this time the assembly projection (27) extended to sufficient lengthto be assembled to support panel (30) parallel to optical axis (1) notleaning.

Above mentioned that the first housing integral to the second housingfor a instance, but to be assembled to depart capable of assembling.Above mentioned that the first housing (20) and the second housing (23)is formed as rectangular parallelepiped shape for a instance, but to beassembled to another shape.

The lens module (10) control the focus length moving in a direction ofan optical axis (1) in a inner space of the first housing (20), and themagnet (11) is reclaimed for a side surface of the lens module (10)confronting to the support panel (30). At this time polarity of themagnet (11) is departed in a perpendicular direction of an optical axis(1). The first guide (12) is extended to respective side having trench“V”. And the first guide (12) and the second guide (45 b) guide the lensmodule (10).

The support panel (30) engaged in the drive portion (40) arranged incenter part and support portion (45) supporting the lens module (10) ina inner space of the first housing (20).

The support portion (45) cover the drive portion (40). The second guide(45 b) having V-shaped trench inner part protrude from both side of thebottom surface (45 a) in support part confronting to the first guide(12). The assembly groove (45 c) is formed at the outer surface of thesecond guide (45 b) in the position confronting to the assemblyprojection (27). Therefore above mentioned assembling the first housing(20) and the support panel (30) is good to work in assembling thecamera.

At this time the second guide (45 b) has at least one ball (45 d),therefore linear movement of the lens module is more easy.

The upper stopper (45 e) and The lower stopper (45 f) is extended fromupper edge and lower edge of the bottom surface (45 a) of supportportion along extending direction of the second guide (45 b).

The drive portion (40) include drive portion printed circuit (40 a) andthe coil (40 b) fixed to printed circuit board (40 a). When current isapplied to the coil (40 b), an electromagnetic field is generated aroundthe coil (40 b). The electric field and magnetic field generated bymagnet (11) react together and generate driving force in a direction ofan optical axis (1) under the Fleming's right hand rule.

At this time the first yoke (13) is mounted between the lens module (10)and the magnet (11) to induce magnetic field of the magnet (11) alongthe direction of drive portion (40), the second yoke (41) is mountedbelow the lower part of drive portion printed circuit fixed to coil (40b) to induce electric field of the coil (40 b) along the direction ofmagnet (11).

The drive portion printed circuit (40 a) has terminal (40 c) of thedrive portion printed circuit (40 a) to engage with circuit board (63)of the image sensor module (60) as above mentioned.

The hall sensor portion (50) is mounted on the drive portion (40) todetect the displacement of the lens module. The hall sensor is adaptedas sensor to detect the displacement of the lens module in this example,but sensor is not defined by hall sensor, as a occasion demands a sensorknown to public such as light sensor is able to be adapted.

The hall sensor portion (50) detect the variation of the position of themagnetic mounted on the lens module and output voltage signal. The hallsensor portion (50) is mounted on the drive portion printed circuit (40b) Being covered with the coil (40 b) to increase efficiency of space.At this time the hall sensor portion (50) is electrically provided bythe drive portion printed circuit (40 b) and transfer voltage signal tothe drive portion printed circuit (40) as the displacement to the lensmodule (10)

The hall sensor portion (50) detecting displacement of the lens module(10) and the control portion controlling the current of the driveportion (40) coil (40 b) as output of the hall sensor portion (50) areintegrated one chip, as above mentioned the hall sensor (50) and thecontrol portion (100) are integrated one chip the degree of using thespace is raised and decrease the length of wire and minimize the effectof the noise in controlling of the focus position.

In case the restriction of the space is not hard, the hall sensorportion (50) and the control portion (100) is separated and is capableof mounting the drive portion (40) and image sensor module (60)separated from the control portion (100).

FIG. 4 is a perspective view a camera system according to according tothe first embodiment of the present invention. hereinafter the operatingof the camera will be described.

The camera lens module (10) according to the first embodiment of thepresent invention in initial state is in contact with the magnet (11)and the second yoke (41) according to the attraction force in adirection to the drive portion (40), at the same time the magnet (11) ismoved to the center of the second yoke (41) and the lens module (10) isin contact with the lower stopper (45 f)

That is to say the lens module (10) in a initial state is at a stop inthe position where the reclaimed side surface of the magnet (11)confront the second yoke (41) and the lower part is in contact with theupper stopper (45 f). At this time the initial state is the state not tobe applied to the drive portion, the lens module (10) is not activateddriving force. In case the contacting force to be contacting with thelower portion of the lens module and the lower stopper, the contactingforce is increased to mount the member having magnetic force at thelower stopper (15 f) and to extend the second yoke (41) in a directionto the lower stopper (45 f).

In a initial state if the current is applied to the drive portion (40)coil (40 b) is generated by Fleming's right hand rule and the lensmodule (10) is moved to in a direction of an optical axis (1). Thedisplacement of the lens module (10) is decided according to themagnitude of the current applied to the coil (40 b) and the focusdistance is to be controlled.

At this time, as above mentioned the lens module (10) is attracted tothe drive portion, this attraction activate interrupt the movement ofthe lens module (10) in a direction of an optical axis (1).

At least one ball (45 d) is equipped between the first guide (12) andthe second guide (45 b) and less driving force can drive the lens module(10) as rolling activation in moving the lens module (10).

The concave of the first guide (12) and the second guide (45 b) areV-shape, and the ball (45 d) can roll along the concave. The first guide(12) and the second guide (45 b) guide the lens module (10) in adirection of an optical axis (1) with the lens module guide (23), theshape of concave is “V”, but as occasion demands the shape of concavecan adapt various shape.

the size of the ball (45 d) is formed to contact inner face of concavein the first guide (12) and the second guide (45 b) and selected tomaintain no to contacting the lens module (10) and the drive portion(40) at the same time.

If the current applied to drive portion (40) coil (40 b) is to be cut,the driving force vanish. Therefore the lens module (10) is returned tothe initial state because of gravity and the attracting force betweenthe magnet (11) and the second yoke (41).

FIG. 5 and FIG. 6 are block diagram illustrating a camera systemactivating composition according to the first embodiment of the presentinvention. As shown FIG. 5, If the control signal photographing asubject by user is inputted to the input portion (110), the controlportion (100) transfer the control signal to the drive portion (40)along predetermined algorithm of the memory (120) and control theposition of the lens module (10).

The control portion (100) detect the focus position of a subject usingthe image signal transferred from image sensor (61) along the variationof the position of the lens module (10) and save detected focus positionto the memory (120)

In case of detecting the focus position the control portion (100)transfer control signal to the drive portion (40) and perform auto focusfunction. As shown FIG. 5 the image sensor module (60) has the inputportion (110) and the memory (120), but as occasion demands they are tobe composed respectively.

As above mentioned in case the control portion (100) is transferred tothe signal to control the lens module, as shown FIG. 6 the variationportion (100 a) of the control portion (100) detect predeterminedstandard output (V_(H,N)) in the memory (120) of the hall sensor portion(50) and the displacement of the lens module (10), compare real output(V_(H)) and the control signal generating portion (100 b) transfercontrol signal (current signal to increase or decrease) to controlportion (40) as the result comparing output.

On occasion demands as shown FIG. 5 and FIG. 6 real output of the hallsensor portion (50) is amplified to predetermined ratio from amplifyportion (130) and is transferred to the control portion (100).

FIG. 7 is block flow chart illustrating control method of auto focus incamera system according to the first method in the first embodiment ofthe present invention. The auto focus function of the camera the focusposition detect step that detect the focus position of a subject and thelens module move step that move the lens module (10) to detected focusposition, hereinafter respective steps will be described.

In the focus position detect step if the input portion (110) is inputtedto control signal to photograph a subject by user, the control portion(100) detect real output (V_(H)) of the hall sensor portion (50) in theinitial state (N=0) of the lens module (10) and save the initialstandard output (S200)

In this embodiment the S200 step is performed in the N=0 position,initial state, as occasion demands the said step is performed in anotherposition. At this time initial position is the position of the lensmodule (10) mentioned above state (that is to say not activating drivingforce).

In case the S200 step is finished, the control portion (100) add thepredetermined output variation of the hall sensor portion in the memorycorresponding respectively a position (N=0, N=1, N=2, . . . , N=N_(END))existing between initial position (N=0) of the lens module (10) and themaximum position (N=N_(END)) and initial standard output saved in theS200 step and set the standard output of the hall sensor portion (50).At this time in case of activating driving force the maximum position ismeaning to the position to move maximum from the initial position of thelens module (10).

In S200 step the fabricate variation and the assembly variation isconsidered to the respective article and component in auto focusingbesides prior art, so precise auto focus is performed.

If initial standard output is set to the same value as to respectivearticle the standard output of the hall sensor portion (50) as torespective article is the same value. But really real position of thelens module (10) as to the same standard output is different because thefabricate variation and the assembly variation is generating torespective articles.

Therefore a division of the focus position is not detected by thecontrol portion (100), ultimately the article is judged to inferiorarticle in manufacturing line and lower the yield.

To solve the above-mentioned problems in this embodiment the initialstandard output is detected directly to considerate the fabricatevariation and assembly fabricate in performing auto focus function, addthe initial standard output and the magnitude of output variation, setthe standard output at respective control position corresponding to thecharacteristic of fabricating and assembling articles. Therefore expenseinspecting quality and error ratio is decreased and the yield of themanufacturing line is improved.

If the S200 step is finished, the control portion (100) transfer controlsignal to the drive portion (40) and at this time the magnitude of thecurrent applied is calculated and saved to the memory.

If the S 300 step is finished, the control portion (100) detect the realoutput (V_(H)) of the hall sensor portion (50), compare real output(V_(H)) and the standard output (V_(H,N=1), that is to say the sumpredetermined output variation (ΔV_(H,N=1)) in memory (120)corresponding to the position at N=1 and the initial standard output)and judge the correct position of the lens module (10) in the positionat N=1 (S250)

In the S 250 step the control portion (100) judge correct position ofthe lens module (10) in case the value of real output (V_(H)) and thestandard output (V_(H,N=1)) is the same, if the value of real output(V_(H)) is in a range of predetermined value as the center of thestandard output (V_(H,N=1)), the control portion (100) is judged tocorrect position.

In the S 250 in case the position of the lens module (10) is notcorrect, the control portion (100) output control signal to increase ordecrease of the current applied to the coil (40 b) to dive portion (40).

In this process for example if position of the lens module (10) not yetarrived at the position N=1, the control portion (100) increase thecurrent and the driving force activating the lens module (10) is to beincreased, if position of the lens module (10) passed by the positionN=1, the control portion (100) decrease the current and the drivingforce activating the lens module (10) is to be decreased.

The increasing magnitude or decreasing magnitude of the current is setto be same value at respective control step, or is set to change inorder of precedence to each control step.

In this embodiment the method of auto focusing control in camera havethe advantage that position of the lens module (10) because the methodis comparing the standard output of the hall sensor portion (50) andbeing close loop type that control of position of the lens module (10)to be in predetermined error range or to be same value besides priorart, open loop type.

In this embodiment the method of auto focusing control in cameraposition of the lens module (10) is to be controlled correctly becausethe control portion (100) control differently by above mentioned appliedto the coil (40 b) in various case such as structural friction forceactivating of the lens module movement or the gravity effecting the lensmodule as to shooting angle is same article. And therefore expenseinspecting quality and error ratio is decreased and the yield of themanufacturing line is improved.

In S 250 step, in case the lens model is correctly positioned at the N=1the control portion (100) judge fitting of the image signal focustransferred from the image sensor module (60).

The control portion (100) can judge fitting of the focus as disclosedtype, in this embodiment the control portion (100) judge fitting of thefocus to detect phase difference to use image signal transferred fromimage sensor, the phase difference detecting type is the method that thelight of providing by the lens module from a subject is to be separatedand judge the fitting of the focus. This method is disclosed broadly bythose skilled in the art.

In S270 in case the focus is fitted the control portion (100) save thepresent position (N=1) as the focus position (N=N_(END)) and perform theS 230 step position of the lens module to be arrive the maximum position(N=N_(END)) (S280, S290) and incase of not fitting the S 290 step isperformed.

In this embodiment in case the focus position is saved, the controlportion (100) move the lens module (10) to the maximum position in phaseand repeat the S 230 step. As occasion demands to decrease the detectingtime of focus position focus position is to be finished if the focusposition is detected, and perform the lens module move step.

In this performing process, auto focus control method in cameraaccording to the embodiment the control portion (100) is not equippedwith calculating portion comparing complicated calculating process, andis equipped with comparing portion (100 a) compare the magnitude of thestandard output and real output. Because the complicated calculatingprocess is omitted and the expense is decreased and the lens module isconverged to the control position more quickly.

In case the position of the lens module is not correct the number of therespective position is increased and detect all range to avoid notdetecting case, in this embodiment the auto focus control method incamera is the method that the number of the respective position isdecrease because precisely position control of the lens module iscapable, and the decreasing quantity of number of the N is concluded toshorten the detecting time because of credibility as the same level.

Accordingly auto focus control method in camera according to theembodiment is able to adapt camera shortening the shooting time orcontinuous shooting such as image communication.

Hereinafter the lens module move step is described that the lens moduleis moved to detected focus position.

As the S200 step and S290 step if the detecting of the focus position isfinished the control portion (100) transfer control signal to the driveportion (40) to move the lens module (10) to detected focus position(N=N_(FOCUS)), the drive portion (40) as this the current is applied tothe coil (40 b). At this time the magnitude of the current as abovementioned is desirable for the memory (120) to save the focus position(N=N_(FOCUS))

If S300 step is finished the control portion (100) detect of the realoutput (V_(H)) of the hall sensor portion (50), detected real output iscompared to the standard output corresponding to N=N_(FOCUS) position.

In S320 step the method the control portion (100) to judge of correctposition is the same as S200 and S290.

In S320 step if the lens module (10) is not correct the control portion(100) transfer image signal to the coil (40 b) to increase or decreasethe magnitude of the current, and repeat the S310 step.

At this time the method control portion (100) increasing or decreasingof the magnitude of the current is the same method.

In S320 step judged the position of the lens module (10) is correct atN=N_(FOCUS) position the control portion (100) perform control tomaintain of the lens module position till completing to photograph asubject.

FIG. 8 is block flow chart illustrating control method of auto focus incamera system according to the second method in the first embodiment ofthe present invention.

The control method of auto focus in camera system according to thesecond method If the control signal is to be inputted to the inputportion (110) to photograph a subject to use a camera by user thecontrol portion (100) detect real output (V_(H)) of the hall sensorportion (100) at initial position (N=0) of the lens module (10) andcompare with the standard output (V_(H,N=0)) predetermined to the memorycorresponding to initial position (S1200, S1200)

In S1210 step in case the real output and the standard output isdifferent the control portion (100) is located a position (N=0, N=1,N=2, . . . , N=N_(END)) between initial position (N=0) and the maximumposition (N=N_(END)) and calibrate the standard output of the hallsensor portion (50) predetermined to the memory (120). And if the valueis same, the S230 step is performed.

As occasion demands the control portion (100) judge the same if the realoutput and standard output is in the range of the predetermined rangebesides this embodiment.

In calibrating method this embodiment assume output of the hall sensorportion (50) is changed linearly as the position of the lens module(10). So the standard output is increased and decreased to difference ofreal output and standard output in N=0 position. But in case output ofthe hall sensor portion (50) is changed not linearly as the position ofthe lens module (10), is desirable to be considered at this point.

In the second method explain that S1200 and S1220 are performed at theposition N=0, But in the first method explained as above mentioned asoccasion demands above step is performed at another position.

In S1200 step and S1220 step meet the S200 step of the first method. Theauto focus function is to be performed considering the fabricatevariation and the assembly variation of component of respective articleto control the focus precisely

The output of the hall sensor is saved as standard output in the memory(120) because respective component is fabricated and assembled inspecific size.

But respective article have the fabricate variation and the assemblyvariation, and in this case if the lens module is controlled as savedstandard output standard output of the hall sensor portion (50) and realoutput is different and the control portion (100) is not detect it. As aresult it is judged to error, and the yield is decreased inmanufacturing line.

Accordingly in case the auto focus function control method is adapted inthis embodiment the fabricate variation and the assembly variation isconsidered performing auto focus function in S1200 step and S1220 step,as a result expense to inspect quality in manufacturing line and errorratio is decreased and the yield in manufacturing line is improved.

In another step after S1220 step the method is same as the first method,but is only differ that respective standard output is saved in thememory.

In this embodiment as shown FIG. 1 and FIG. 3 the camera and the methodfor controlling of auto focus for example. But in this embodiment themethod for controlling of auto focus is not defined, is adapted forfocus control of the optical device including the lens module and driveportion of the lens module without departing from the spirit and scopeof the invention.

In this embodiment drive portion is explained as VCM for example, but inthis embodiment the method for controlling of auto focus is not definedand piezo motor (ultrasonic motor) is adapted for drive portion. In thisembodiment the control of driving force is control the magnitude of thecurrent. And depended on the drive portion driving portion is controlledto change voltage or frequency.

Hereinafter the camera according to the second method in the firstembodiment of the present invention is described as illustrated in FIG.9. The camera illustrated in FIG. 9 adapt for guide bar (414) todecrease friction force in moving the lens module and is numbered samenumber as same component in the first embodiment.

The first projection (412) shaped plate having the first guide bar hall(412 a) is formed at the both side reclaimed the magnet (11) in the lensmodule (10) and The second projection (413 b) shaped plate having thesecond guide bar hall (413 a) is formed at confronting position in thesupport panel (30). In this embodiment the first projection and thesecond projection is formed at respective the upper part and the lowerpart in a pair.

In case the lens module (10) and the support panel (30) are assembled apair of the first projection (412 b) is inserted between the secondprojection (413 b) and the center of them are to be in a line and thelens module (10) and the support panel (30) is assembled. At this timeit is desirable for the second guide bar hall in the lower part not topenetrate.

In the second embodiment as the first embodiment the first projectionand the second projection is leaved space the lens module (10) and thedrive portion (40) not to contact.

As the above structure the lens module (10) is restricted moving up anddown, and driving force of the lens module (10) is decreased.

The resilient member (425) is equipped between the lens module (10) andthe first hosing cover (21) to contact the upper part of the firstprojection and the upper part of the second projection in a initialstate the current not to be applied to the coil (40 b)

another construction and control method besides above mentioned is notexplain as the same to the first embodiment.

INDUSTRIAL APPLICABILITY

As described the camera and the auto focus control method of the presentinvention is adapted to the telecommunication handset because theposition of the lens module is controlled precisely corresponding anycase such as the gravity effected from moving of the lens moduleaccording to the shooting angle in a same article and the state of thefabricating and assembly. Accordingly the camera is adapted to theoptical device such as the digital camera.

The camera and the auto focus control method of the present inventioncan decrease the time to detect the focus position. And the camera isadapted to the camera requiring for decrease the photograph time becauseof not performing the complicated calculating and quickly converging tothe control position of the lens module to control the current appliedto the drive portion to compare the standard output of the positionsensor and the real output.

The invention claimed is:
 1. A camera system comprising: a lens modulecapable of movement; a drive portion generating driving force to movesaid lens module; a position sensor portion detecting a position of thelens module and outputting the detected position as an electricalsignal; an image sensor portion outputting an image of a subjectcaptured through the lens module as an electrical signal; and a controlportion determining a focus position of the subject from the output ofthe image sensor portion, calculating a difference between a real outputof the position sensor portion corresponding to the determined focusposition and a standard output of the position sensor portioncorresponding to the determined focus position, and controlling themagnitude of the driving force according to the difference, wherein thestandard output of the position sensor portion is a predeterminedstandard output previously stored in a memory and corresponding to thedetermined focus position.
 2. The camera system of claim 1, wherein thecontrol portion is integrated into one chip together with the positionsensor portion, and controls the magnitude of the driving force bycontrolling the strength of power applied to the drive portion.
 3. Acamera system comprising: a lens module capable of linear movement in adirection of an optical axis; a drive portion generating a driving forceto move the lens module; a position sensor portion detecting a positionof the lens module and outputting the detected position as an electricalsignal; an image sensor portion outputting an image of a subjectcaptured through the lens module as an electrical signal; and a controlportion determining a focus position of the subject from the output ofthe image sensor portion, comparing a real output of the position sensorportion corresponding to the determined focus position and a standardoutput of the position sensor portion corresponding to the determinedfocus position to determine whether the lens module is correctlysituated in the focus position, and controlling the magnitude of thedriving force according to the determination result, wherein thestandard output of the position sensor portion is a predeterminedstandard output previously stored in a memory and corresponding to thedetermined focus position.
 4. The camera system of claim 3, furthercomprising a housing having a space for accommodating the lens module,the drive portion, and the position sensor portion, wherein the controlportion is integrated into one chip together with the position sensorportion and is accommodated in the housing.
 5. The camera system ofclaim 4, wherein the housing comprises a first housing forming a spacefor accommodating the lens module, the drive portion, and the positionsensor portion and a second housing forming a space for accommodatingthe image sensor portion, and the second housing is situated on thelower part of the first housing such that the lens module and the imagesensor portion are aligned with the optical axis, and an opening isformed on each of an upper surface and a lower surface of the firsthousing and an upper surface of the second housing to provide a shootingroute of the image sensor portion.
 6. The camera system of claim 5,wherein at least one first guide member is arranged on a side surface ofthe lens module having a magnetic for guiding movement of the lensmodule in the direction of the optical axis and at least one secondguide member is arranged at a position corresponding to the first guidemember on an inner side surface of the first housing having a coil, aconcave extending in the direction of the optical axis is formed in thefirst guide member and the second guide member, a stopper is provided inan upper part and a lower part of the second guide member to limit amovement range of the lens module between a maximum position and aninitial position, and at least one ball is inserted between the firstguide member and the second guide member to roll in the direction of theoptical axis by contacting the concave, and a first penetrating hole anda second penetrating hole are formed in the first guide portion and thesecond guide portion, respectively, and the lens module is coupled tothe first housing by a guide bar inserted into the first penetratinghole and the second penetrating hole such that the lens module movesalong the guide bar in the direction of the optical axis.
 7. An autofocus control method for a camera which comprises a lens module and animage sensor portion for outputting an image of a subject captured bythe lens module as an electrical signal, the auto focus control methodcomprising: a first step of determining a focus position of the subject;and a second step of comparing a real output of a position sensordetecting a position of the lens module with a standard output of theposition sensor corresponding to the focus position while moving thelens module to the determined focus position to determine whether thelens module is correctly situated in the focus position, and controllingthe position of the lens module according to the determination result,wherein the first step further comprises determining an output of theimage sensor portion while moving the lens module to any one of aplurality of lens module positions including an initial position and amaximum position of the lens module according to a set order previouslystored in a memory, and detecting a lens module position matched to thefocus of the subject as the focus position, wherein the standard outputof the position sensor is a predetermined standard output previouslystored in a memory and corresponding to the determined focus position.8. The auto focus control method of claim 7, further comprising a thirdstep of repeatedly determining whether the lens module is correctlysituated in the focus position while moving the lens module by a setdistance until the lens module is correctly situated in the focusposition if the lens module is not correctly situated in the focusposition.